The invention relates to a method for generating an identifier, a method for blocking a cryptographic device, a computer program product, a blocking system, and a computer system.
The use of various online services, for example for online shopping or for e-government applications, is known per se from the prior art. Typically, a user must identify himself to the computer system which provides the online service via the Internet, for example, using an authentication token. The authentication token may be a chip card or a USB stick, for example. If the authentication token is lost, the user must notify the computer system in question in order to block unauthorized use of the authentication token by third parties.
A system is known from US 2004/0123098 A1 which allows a third party to verify the existence of an association between a first party and a second party. The first party has a first and a second cryptographic key, and the second party has a third and a fourth cryptographic key. To allow the association to be verified, the second party generates a number which, together with a second, third, and fourth cryptographic key, defines a first, a second, and a third cryptographic parameter. By using these parameters and a second and third cryptographic key, the third party is able to verify an association between the first and second parties.
DE 10342710 A1 describes a device and a method for protecting electronic transactions which are carried out using a transaction identification means. At least one RFID tag which is read-only and a further security feature of the transaction identification means (for example, a number, an expiration date of the identification means, a hologram, a magnetic strip, etc.) are evaluated.